Jig for adjusting curvature of substrate

ABSTRACT

Jig for adjusting curvature of a substrate permits to measure an amount of sag of the substrate coming from variation of a length of the slot or the support bar by varying the length of the slot or the support bar, thereby permitting easy fabrication of the cassette according to a trend of fabricating thinner substrate.

[0001] This application claims the benefit of the Korean Application No.P2001-88520 filed on Dec. 29, 2001, which is hereby incorporated byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a jig for adjusting curvature ofa substrate, and more particularly, to a jig for adjusting curvature ofa substrate, in which curvature of the substrate in a cassette used infabrication of a liquid crystal display (LCD) device is measured, foreasy fabrication of the cassette.

[0004] 2. Background of the Related Art

[0005] Applications of the LCDs have been diversified from watches,calculators, PC monitors, and notebook computers to TVs, monitors foraviation, PDAs (Personal Digital Assistants), and mobile stations owingto features of low voltage operation, low power consumption, realizationof full colors, light weight, thin, and compact.

[0006] The LCD is provided with a liquid crystal display panel fordisplaying a picture, and a circuit part for driving the liquid crystaldisplay panel.

[0007] The LCD panel has a first substrate having thin film transistor(TFT) array formed thereon, a second substrate having color filter arrayformed thereon, and a liquid crystal layer formed between the twosubstrates.

[0008] The first glass substrate having the TFT array formed thereon isprovided with a plurality of gate lines arranged in one direction atfixed intervals, a plurality of data lines arranged in a directionperpendicular to the gate lines at fixed intervals to define pixelregions, a plurality of pixel electrodes in respective pixel regions fordisplaying a picture, and a plurality of thin film transistors inrespective pixel regions at cross points of the gate lines and the datalines for being turned on/off in response to driving signals on the gatelines for transmitting a picture signal from the data lines to the pixelelectrodes.

[0009] The second glass substrate having the color filter array formedthereon is provided with a black matrix layer for shielding a light fromparts excluding the pixel regions, a R, G, B color filter layer formedopposite to the pixel regions for realizing colors, and a commonelectrode formed on an entire surface inclusive of the color filterlayer. Of course, the common electrode is formed on the first substratein an LCD of an IPS mode.

[0010] The first and second substrates are bonded together, with a spacebetween the two substrates, and a liquid crystal layer is formed betweenthe first and second substrates.

[0011] The substrate is a glass plate of which weight portion in the LCDpanel is great. Therefore, in order to reduce weight of the LCD panel,it is required to reduce weight of the glass substrates, at the end, torequire thin glass substrates.

[0012] A process for fabricating the LCD may be divided into threeprocesses of a substrate fabrication process, a cell fabricationprocess, and a module fabrication process.

[0013] The substrate fabrication process may be divided into processesof fabrication of the TFT, and the color filter on the cleaned glasssubstrates. The TFT fabrication process is a process for fabricating aplurality of thin film transistors and pixel electrodes on a firstsubstrate, and the color filter fabrication process is a process forforming R, G, B color filter layer by using dye or pigment on a secondsubstrate having a light shielding layer formed thereon, and the commonelectrode (ITO).

[0014] The cell fabrication process is a process for fabricating cellsof the LCD by scattering spacers between two substrates of the firstsubstrate having the TFT fabrication process finished, and the secondsubstrate having the color filter fabrication process finished, bondingthe two substrates, and injecting liquid crystal between the twosubstrates, and, finally, the module fabrication process is a processfor fabricating a circuit part for processing signals, and connectingthe LCD panel and the signal processing circuit part, to fabricate amodule.

[0015] In the LCD fabrication process, it is required that thesubstrates are conveyed or carried to an apparatus required for aprocess, progressively, or in a form of group, for passing through thesubstrate fabrication process, the cell fabrication process, and themodule fabrication process. Moreover, since entire fabrication line cannot be stopped for repair of a part of the fabrication apparatus in viewof the fabrication process, it is required that the fabricationapparatus is provided with a means for temporary storage of thesubstrates.

[0016] To meet this requirement, a cassette is used. By moving thecassette with a plurality of the substrates stored therein, theplurality of substrates are movable at a time. Though dependent on thecassettes, when the plurality of substrates are stored in the cassette,the substrates are bend.

[0017] Such a cassette will be explained, with reference to the attacheddrawings. FIG. 1 illustrates a front view of the cassette.

[0018] Referring to FIG. 1, the cassette has hexahedral body 13 forstoring the plurality of substrates in horizontal position. There arevertical frames 13 a vertical to ground at at least opposite twosurfaces of the body 13, a plurality of slots 15 for supporting edges ofthe substrate 11, and stoppers 17 at opposite side of a substrateentrance for stopping the substrate 11 inserted into the cassette.

[0019] The vertical frame 13 a having the slots 15 formed thereon may beformed, not only at the four sides of the hexahedral body, but also atcorners of the cassette, more. The slots 15, around 20 in number on eachof the vertical frame 13 a, have a fixed length and width, forsupporting edges, or sides, of the substrates 11.

[0020] As explained, the substrate is a thin glass plate for reducingweight of the LCD, which is liable to bend. Therefore, the length of theslot 15 is a major factor of fixing curvature of the substrate 11, theshorter the slot 15, the greater the curvature of the substrate 11, andthe longer the slot 15, the smaller the curvature of the substrate 11.

[0021] That is, FIG. 2 illustrates sag of the substrate schematically,wherein the substrate 11 is supported on the slots 15, which are fixedto the vertical frames 13 a.

[0022] A depth Y of the sag of the substrate 11 can be measured with aheight gage, and since a robot is to bring the substrate 11 into thecassette and place on the slot 15, for not giving interference to themovement of the robot, it is required that the depth Y of sag is kept tobe within a certain value for preventing the substrates from overlappingwith the other due to the sag.

[0023] After all, the longer the length of the slot 15, the smaller thedepth of the sag Y as the substrate 11 is supported on the slots 15 themore, and the shorter the length of the slot 15, the greater the depthof the sag Y as the substrate 11 is supported on the slots 15 the less.

[0024] Therefore, it is required that the cassette is fabricated, notonly to fit a size of the substrate 11, but also to have a proper lengthof the slot 15 depending on the curvature of the substrate.

[0025] However, the related art cassette has the following problem.

[0026] Since the slots in the cassette is fixed to the vertical frame,it is required to fabricate a mock up of the cassette according to thecurvature of the substrate, and test the mock up cassette for aplurality of time before the cassette is fabricated.

[0027] That is, for finding a slot suitable to the substrate, aplurality of fabrication of the mock up cassette is required for copingwith slot length variation with a thickness of the substrate, whichincreases cost and requires longer production time, that drops theproductivity.

SUMMARY OF THE INVENTION

[0028] Accordingly, the present invention is directed to a jig foradjusting curvature of a substrate that substantially obviates one ormore of the problems due to limitations and disadvantages of the relatedart.

[0029] An object of the present invention is to provide a jig foradjusting curvature of a substrate, which can measure an adjustment ofcurvature of the substrate for fabricating a cassette that optimizescurvature of the substrate by varying a slot length with a thickness ofthe substrate.

[0030] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned by practice of the invention.The objectives and other advantages of the invention will be realizedand attained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

[0031] To achieve these and other advantages and in accordance with thepurpose of the present invention, as embodied and broadly described, thejig for adjusting curvature of a substrate includes a cassette storingthe substrate, a main shaft fixed to the cassette in a directionparallel to the substrate, a movable bar movable parallel to the mainshaft, a reference bar rotatably fitted to the main shaft moving themovable bar back and forth, and a plurality of slots each fixed to themovable bar supported on the main shaft having a length adjustableaccording to the back and forth movements of the movable bar.

[0032] In another aspect of the present invention, there is provided ajig for adjusting curvature of a substrate including a cassette having aplurality of vertical frames on both sides of a substrate entrance, atleast two main shafts fixed to the vertical frames at both sides of thecassette, at least two movable bar movable parallel to the main shafts,at least two reference bars rotatably fitted to the main shaftsrespectively for moving the movable bars back and forth, and a pluralityof slots each fixed to the movable bar supported on the main shafthaving a length adjustable according to the back and forth movements ofthe movable bar.

[0033] In further aspect of the present invention, there is provided ajig for adjusting curvature of a substrate including a cassette having aplurality of vertical frames on both sides of a substrate entrancestoring substrates, and a stopper at an opposite side of the substrateentrance stopping the substrate, each of the frame having a plurality ofslots, a main shaft fixed to the stopper in a direction parallel to thesubstrate, a movable bar movable parallel to the main shaft, a referencebar rotatably fitted to the main shaft vertical thereof moving themovable bars back and forth, and a support bar fixed to the movable bar,and supported on the main shaft, having a length adjustable according tothe reference bar.

[0034] Thus, the jig for adjusting curvature of a substrate of thepresent invention can fabricate a cassette for thin substrates easilybecause variation of curvature of the substrate varied with a length ofthe slots can be measured easily by varying the length of the slots orsupport bar.

[0035] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory and are intended to provide further explanation of theinvention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and together with the description serve to explain theprinciples of the invention:

[0037] In the drawings:

[0038]FIG. 1 illustrates a front view of a cassette;

[0039]FIG. 2 illustrates sag of the substrate schematically;

[0040]FIG. 3 illustrates a plan view of a jig for adjusting curvature ofa substrate in accordance with a first embodiment of the presentinvention; and

[0041]FIG. 4 illustrates a plan view of a jig for adjusting curvature ofa substrate in accordance with a second embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE EMBODIMENT

[0042] Reference will now be made in detail to the embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. FIG. 3 illustrates a plan view of a jig for adjustingcurvature of a substrate in accordance with a first embodiment of thepresent invention.

[0043] Referring to FIG. 3, the cassette (not shown) has a plurality ofvertical frames 103 at both sides of a substrate 101 entrance verticalto ground. The jig for adjusting curvature of a substrate in accordancewith a first embodiment of the present invention includes a main shaft105 fixed to the vertical frames 103 in a direction parallel to thesubstrate 101, reference bars 107 vertical to the main shaft 105 andparallel to a plane of the substrate 101, a movable bar 109 movablealong the reference bars 107 parallel to the substrate 105, and aplurality of slots 111 fixed to the movable bar 109 supported on themain shaft 105 having a length adjustable according to curvature of thesubstrate 101. There are at least two reference bars 107 fitted to thecassette.

[0044] Though not shown, there is another jig for adjusting curvature ofa substrate fitted at a side of the cassette opposite to a side the jigfor adjusting curvature of a substrate is fitted thereto.

[0045] The jig for adjusting curvature of a substrate in accordance witha first embodiment of the present invention permits to measure the depthof sag of the substrate as a plurality of the jigs are positioned onopposite sides the substrate 101, making lengths of the slots 111supporting the substrate 101 identical. The depth of sag of thesubstrate 101 is measured by using a height gage.

[0046] Each of the plurality of reference bars 107 has a thread of afixed pitch in a longitudinal direction thereof, for moving the movablebar 109 back and forth by rotating the reference bar 107 at knobs 107 a.

[0047] Moreover, there is a guide 105 a fitted with an adjusting ruler(not shown) at a center of the main shaft 105 for measuring movement ofthe movable bar accurately.

[0048] Therefore, by determining an amount of sag of the substrate 101appropriate to the substrate 101 by adjusting the length of the slot 111according to change of a thickness of the substrate 101, fabrication ofthe cassette for conserving and storing the substrate 101 is made easy.

[0049] The operation of the jig for adjusting curvature of a substratein accordance with a first embodiment of the present invention will beexplained.

[0050] At first, a plurality of ends of the main shaft 105 are fixed tothe vertical frames 103 at opposite corners of the cassette by clamp 105b, and lengths of the slots 111 are put the same.

[0051] After inserting the substrate 101 into the cassette, an amount ofthe sag of the substrate 101 is measured by using a height gage (notshown), and the length of the slot 111 is measured repeatedly whileturning the knobs 107 a. At the end, after verifying an optimum depth ofthe sag, the cassette can be fabricated by applying a final length ofthe slot 111.

[0052] Thus, the jig for adjusting curvature of a substrate inaccordance with a first embodiment of the present invention can verifycurvature of the substrate effectively by varying the length of the slot111 with change of a thickness of the substrate 101, and permits an easyfinding of the length of the slot 111 for an optimum sag.

[0053] In the meantime, by fitting one more supporter bar at a rear sideof the cassette additionally as the substrate 101 becomes thinner, thesubstrate 101 can be placed with better safety by reducing the sag ofthe substrate within the cassette.

[0054]FIG. 4 illustrates a plan view of a jig for adjusting curvature ofa substrate in accordance with a second embodiment of the presentinvention.

[0055] A cassette (not shown) having the jig for adjusting curvature ofa substrate in accordance with a second embodiment of the presentinvention applied thereto includes a plurality of vertical frames 103vertical to ground on both sides of a substrate 101 entrance, aplurality of slots (not shown) of a length fitted to the vertical frames103, and a plurality of stoppers 113 on an opposite side of the entrancefor stopping the substrate 101 inserted into the cassette.

[0056] Referring to FIG. 4, the jig for adjusting curvature of asubstrate in accordance with a second embodiment of the presentinvention includes a main shaft 105 fixed to the stoppers 113 parallelto the substrate 101, reference bars 107 vertical to the main shaft 105and parallel to a substrate 101 plane, a movable bar 109 movable alongthe reference bars 107 parallel to the main shaft, and a support bar 115fixed to the movable bar 109 and supported on the main shaft 105 forhaving a length thereof adjusted according to curvature of the substrate101.

[0057] Though not shown, a connection bar may be fitted to each of theplurality of the stoppers 113 additionally, and the support bar 115 maybe fixed to centers of the connection bars for supporting the substrates101.

[0058] The support bar supports the substrate 101 passed throughperiphery of the substrate 101 having no active regions formed therein.That is, the substrate 101 may be supported by the slots on the verticalframes 103 at opposite edges thereof in symmetry, and by the support bar115 at one side periphery thereof in asymmetry.

[0059] Accordingly, the depth of sag of the substrate 101 at thecassette entrance can be measured by the height gage.

[0060] Each of the plurality of reference bars 107 has a thread of afixed pitch in a longitudinal direction, for moving back and forth themovable bar 109 by rotating the reference bar 107 at knobs 107 a.

[0061] Moreover, there is a guide 105 a fitted with an adjusting ruler(not shown) at a center of the main shaft 105 for an accuratemeasurement of the movement of the movable bar 109.

[0062] Therefore, by determining an amount of sag of the substrate 101appropriate to the substrate 101 by adjusting the length of the slot 111according to change of a thickness of the substrate 101, fabrication ofthe cassette for conserving and storing the substrate 101 is made easy.

[0063] Thus, the sag of the substrate 101 can be measured by using theplurality of stoppers 113 in the jig for adjusting curvature of asubstrate in accordance with the second embodiment of the presentinvention.

[0064] As has been explained, the jig for adjusting curvature of asubstrate of the present invention permits effective verification of theamount of sag of the substrate by varying the length of the slots (111in FIG. 3) or the support bar 115 according to a trend of fabricatingthinner substrate 101, and fabricate the cassette by measuring lengthsof the slots or the support bars for the optimum amount of sag.

[0065] The jig for adjusting curvature of a substrate of the presentinvention has the following advantage.

[0066] The jig for adjusting curvature of a substrate of the presentinvention can meet requirements coming from the trend of fabricatingthinner substrates because measurement of curvature of the substratecaused by variation of the slots or support bars is made easy by varyinglengths of the slots or the support bars.

[0067] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the jig for adjustingcurvature of a substrate of the present invention without departing fromthe spirit or scope of the invention. Thus, it is intended that thepresent invention cover the modifications and variations of thisinvention provided they come within the scope of the appended claims andtheir equivalents.

What is claimed is:
 1. A jig for adjusting curvature of a substratecomprising: a cassette storing the substrate; a main shaft fixed to thecassette in a direction parallel to the substrate; a movable bar movableparallel to the main shaft; a reference bar rotatably fitted to the mainshaft for moving the movable bar back and forth; and a plurality ofslots each fixed to the movable bar supported on the main shaft having alength adjustable according to the back and forth movements of themovable bar.
 2. The jig as claimed in claim 1, wherein the main shaftfurther includes an adjusting ruler measuring movement of the movablebar.
 3. The jig as claimed in claim 1, wherein the main shaft furtherincludes clamps fixing the main shaft to the cassette.
 4. The jig asclaimed in claim 1, wherein the reference bar includes a thread of afixed pitch moving the movable bar.
 5. The jig as claimed in claim 4,wherein the reference bar further includes a knob rotating the referencebar.
 6. The jig as claimed in claim 1, wherein the reference barincludes at least two reference bars moving the movable bar in parallelto the main shaft.
 7. The jig as claimed in claim 1, wherein thecassette includes a plurality of vertical frames.
 8. The jig as claimedin claim 7, wherein the vertical frames have the main shaft fixedthereto.
 9. A jig for adjusting curvature of a substrate comprising: acassette having a plurality of vertical frames on both sides of asubstrate entrance; at least two main shafts fixed to the verticalframes at both sides of the cassette; at least two movable bar movableparallel to the main shafts; at least two reference bars rotatablyfitted to the main shafts respectively for moving the movable bars backand forth; and a plurality of slots each fixed to the movable barsupported on the main shaft having a length adjustable according to theback and forth movements of the movable bar.
 10. A jig for adjustingcurvature of a substrate comprising: a cassette having a plurality ofvertical frames on both sides of a substrate entrance storingsubstrates, and a stopper at an opposite side of the substrate entrancestopping the substrate, each of the frame having a plurality of slots; amain shaft fixed to the stopper in a direction parallel to thesubstrate; a movable bar movable parallel to the main shaft; a referencebar rotatably fitted to the main shaft vertical thereof moving themovable bars back and forth; and a support bar fixed to the movable bar,and supported on the main shaft, having a length adjustable according tothe reference bar.
 11. The jig as claimed in claim 10, wherein the mainshaft includes an adjusting ruler measuring movement of the movable bar.12. The jig as claimed in claim 10, wherein the main shaft furtherincludes clamps fixing the main shaft to the cassette.
 13. The jig asclaimed in claim 10, wherein the reference bar includes a thread of afixed pitch moving the movable bar.
 14. The jig as claimed in claim 13,wherein the reference bar further includes a knob rotating the referencebar.
 15. The jig as claimed in claim 10, wherein the reference barincludes at least two reference bars moving the movable bar in parallelto the main shaft.